The invention relates to a method for removing titanium from hexachlorodisilane through treatment with organic compounds.
Hexachlorodisilane which is produced from silicides always contains traces of titanium and other metallic impurities. Titanium is critical inasmuch as titanium(IV) chloride differs only slightly from hexachlorodisilane in terms of boiling point. In order to separate it off, complex fractional distillation is required.
One option is to workup the silane mixture produced during the separation of silicon since the chlorosilanes used for this can be relatively easily freed from titanium by distillation. During the separation of silicon, disilanes are in turn formed from the chlorosilanes, but in concentrations below 1% by weight. Upon storing these silanes in stainless steel containers, corrosion can lead to titanium again arising in the product, which has hitherto again only been able to be separated off by fractional distillation.
U.S. Pat. No. 3,878,291 (Apr. 15, 1975, Kleber et al.) describes a complex method for obtaining tetrachlorosilane free from titanium and other metals.